<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>伪元素选择器</title>
    <style>
        div {
            width: 400px;
            height: 400px;
            background-color: antiquewhite;
        }
        
        div::after {
            content: '我在后面';
        }
        
        div::before {
            content: '我在前面';
        }
    </style>
</head>

<body>

    <div>
        哇哇哇哇
    </div>





</body>

</html>